I got my JVM410H(new)back in August 2018 and I’m noticing some sufficient tone changes in the amp as it ages through use. Do any of you notice your JVM sort of like, breaking in? I’ve had to make several adjustments, all for the good, as the amp ages especially when I use it at loud volumes for a period of time and get it hot. It seems like the gain goes up, I find myself backing the gain down a little when the amp gets warm to hot. I’ve read in the forum that the amp changes with age, I guess all tube amps actually have a break-in period. Heck I’m a heavy metal player and I find myself using the crunch mode(red)for some rhythms because of such good gain, instead of od1, or od2. I end up using od1, od2 (red)for leads. I know I’m coming in hot on the amp anyways because of my ESP guitars with active pickups, but it seems to react normally, like a tube amp should react with age as it gets hot. This isn’t my first tube amp, I had a DSL100H(new) and it broke in the same way, the gain increased as it aged and got hotter. I got rid of it though because it doesn’t have the versatility that the JVM has. Well I’m just putting that out there. Rock on Marshall!!

Unless maybe the bias is set too hot, you shouldn't notice what you describe.

Gain is created in the preamp section and the JVM poweramp section is designed to have more headroom then your classic Marshall amp (and DSL's). So running at high volumes will not result in more gain. However, it is a common practice to lower the gain at higher volumes, because feedback/sustain is introduced in that situation. Active pickups hit the preamp a bit harder, but that will only result in more gain all of the time.

Most tubes do not require a lot of break in time and power tube aging does not usually occur within months. A lot of JVM owners have perceived a change in tone (not gain) because their ears got used to the JVM. And then you re-adjust the settings to your liking. Did you also get a new cab at the time? Speakers need quite a bit of breaking in, some types sound harsh initially.

As you play at high volumes, the way your ears and brain process sound changes during the session. Call it ear fatigue or whatever, but it is a fact.

As you play at high volumes, the way your ears and brain process sound changes during the session. Call it ear fatigue or whatever, but it is a fact.

This is what immediately sprung to mind. I get this at most gigs and the temptation to tweak settings is almost irresistable. Just have to have faith that what set during sound check is still the same sound you are producing.

This is what immediately sprung to mind. I get this at most gigs and the temptation to tweak settings is almost irresistable. Just have to have faith that what set during sound check is still the same sound you are producing.

Before I started using ear protection, I once did a gig that was so loud that I even started hearing the wrong notes and chords (no, it wasn't my playing ). That was a turning point for me. By that time I had unfortunately already suffered permanent damage to my ears from playing too often too loud. Back in the day (80's and early 90's) there was no decent protection and/or it was considered to be lame.

Ok I understand, maybe it just is my ears, the amp is totally stock, no mods at all, it doesn’t need any. It just seems to get better and better with time. I never thought of ear fatigue before, I have played many loud shows without ear protection. I need to look into that because hearing is the soul of music, I was in the army too and was around a lot of loud tanks, gunfire, and turbines, so I have a little tinnitus (ringing). I love the tone of the JVM410H, it’s a monster, I picked it out over about 20 different amplifiers when I was shopping for an amp, and fell in love with its versatility and tone(sound)not to mention 6OD channels. Guitar center loved me that day I was trying out all the amps. Ha Ha! Much love guitar center!! And Sam Ash too!! Since I ordered the amp from Zzounds! Thanks for the feedback, I’m glad to have a normal JVM410H, that operates well and has quality sound. The cabinets I have are fairly new 2YRS old, they are the MX412A/B cabs, 240 watt, 16 ohm. I’ve had them up to high volume probably about 25 times, I’d say their pretty much broke in. The MX412A/B cabs have a raw, punchy, gritty sound to them(I like them because it’s my sound), different than the 1960 A/B cabs which sound more smoother and laidback, at least that’s what I heard on them at guitar center and Sam ash. Thanks for the advice brothers and rock on!!

Good to hear you finally got what you were after tonewise - we all know that journey, brother... :-)

BTW My advice for ear protection is to not go cheap. It won't work and after a while you'll get frustrated (uncomfortable or bad sound) and stop using it. Your ears are worth to invest a bit more in custom mold ear plugs equipped with specialized 'musicians filters'. These have a flat frequency response, but it will always take away some of the magic - you will get used to that. -15dB or -12dB damping will do the trick. Wear them at practice and at gigs so you will get used to them. Dial in your amp before you put in the plugs and then don't touch the dials anymore.

Any good audiologist should be able to help you with this. If you are a singer, make sure you clamp a pencil or similar between your teeth when the molds are made at the audiologist. Otherwise, the plugs may open up a bit while singing because of your jaw moving. Expect to pay $100 - $150 for the pair.

So your saying I should hook up with a doctor to get proper hearing protection? Never thought they would be a resource for that. I guess if I want the best for my ears an audiologist would be the path I should follow. I should be able to get this on my insurance, to keep cost down. A nice set of professenionally made ear plugs would do me good. Thanks for the tip!